function s1_hello() {
 echo "hello, world!"
}
function s2_tell_who_i_am(){
  echo "$liuyanan020303"
}
function s3_which_distro_do_i_use(){
  cat/etc/os-release |head -n1|grep"NAME"
}
function s4_view_my_cpu_arch(){
  uname -m
}
function s5_show_first_scsi_disk_size(){
lsblk -l|grep disk|\grep'^sad'|awk '{print $5}'
}
function s6_show_main_memory_size_in_megabytes(){
free -m|grep "Mem:" |awk'{print $2}'
}

